1. Field of the Invention
The present invention relates to shackles. More particularly, the present invention relates to shackles having installable pins. Additionally, the present invention relates to shackle apparatus whereby the pin of the shackle can be installed through eyelets of the legs of the shackle body by a remotely operated vehicle (ROV) for the purposes of lifting a subsea object.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
In the age of deep sea oil and gas exploration and drilling, it becomes increasingly necessary to install and to remove very large objects at a significant distance below the surface of the body of water. Various objects that are located below the surface of the water can include oil production trees, subsea platforms, pumping equipment and other apparatus. In the past, these types of devices have been relatively light so that the objects can be easily lifted to the surface of the body of water by a simple crane and hook assembly. The hook can engage a padeye or other connector on the object so that when a lifting force is applied to a line, the object can be raised to the surface.
At present, the requirements for subsea oil and gas production have increased significantly. Additionally, the depth at which drilling activities occur increases continuously. As a result, increasingly heavy objects are required to be placed on the ocean floor for use in the oil and gas drilling and production activities. As such, a need has developed for devices whereby very large objects can be securely transported to the surface of the body of water using lifting devices on a ship or other water-supported device.
Whenever subsea objects are located at a depth of greater than 400 feet, it becomes necessary for remotely operated vehicles (ROVs) to be utilized for carrying out the subsea activities. These remotely operated vehicles usually have at least one arm extending therefrom. These devices can be operated from the surface of a body of water and manipulated so as to properly carry out the subsea activities. In the circumstances where objects must be lifted from a depth of greater than 400 feet, an ROV must be employed so as to assist in the lifting operation. In the past, the arm of an ROV has been utilized so as to place a hook of a line from a crane into a padeye of a subsea object.
Typically, such hooks will only have a capacity of up to three hundred tons, and this lifting is not very secure. Various other mechanisms must be employed so as to provide for greater lifting forces. In particular, shackles have ratings of up to 400 tons. As such, shackles are a preferred method for securement to the subsea object for the purposes of securely lifting the object to the surface. Typically, a container that is positioned below the surface will have a number of padeyes located on a surface thereof. As such, shackles can be applied to separate padeyes so as to distribute the forces more evenly and reduce the load on each shackle. Shackles are well known in the prior art and are commonly utilized on surface activities.
Unfortunately, in the past, it has been difficult to utilize such shackles in the subsea environment. Whenever a shackle is utilized, a relatively complex system must be utilized so as to install the pin in the eyelets associated with each of the legs of the shackle. As such, a need has developed so as to provide such a pin which can be installed into the eyelets associated with the legs of the shackle by a remotely operated vehicle. Such an installation must be secure, reliable and relatively quick.
In the past, various patents have issued relating to shackles and subsea installations. For example, U.S. Pat. No. 4,476,673, issued on Oct. 16, 1984 to R. T. Brown, describes a shackle pin locking construction. In particular, this device utilizes a resilient clip that selectively engages portions of a loop-type shackle. A removable locking pin is secured thereto so as to prevent accidental dislodgement through a loosening of the pin. The clip may be engaged and disengaged without the use of tools. The clip is temporarily resiliently attached to the body of the shackle when not in use.
U.S. Pat. No. 4,705,331, issued on Nov. 10, 1987 to J. N. Britton, shows a self-actuating clamp for attachment to a structural member in a subsea environment. The clamp includes a housing having spaced side members, a transverse compression plate mounted between the members across the top of the housing and external accessory mounting surfaces. A pair of opposed, elongated jaw members have their upper portions disposed within the housing. A trigger assembly is provided for maintaining the jaw members in an open position while the clamp is properly positioned over the structural member.
U.S. Pat. No. 4,943,187, issued on Jul. 24, 1990 to H. P. Hopper, describes a system of ROV intervention on subsea equipment. In particular, a projecting actuation point and a hollow ROV-operable tool is provided a smaller diameter surface of the actuation point provides a coarse guidance and early alignment of the tool.
U.S. Pat. No. 6,023,927, issued on Feb. 15, 2000 to I. Epstein, shows a shackle with a kant loose pin. In particular, this shackle allows for the attachment of a cable or a chain or a rope to the shackle. The shackle has a clevis pin whereby operator can connect a cable or multiple cables to the shackle and clevis pin so as to reduce the number of operators. The spring urges a locking lever to lock the clevis pin and shackle together and to preclude the rotation of the clevis pin and shackle with respect to each other.
U.S. Pat. No. 6,402,428, issued on Jun. 11, 2002 to Morisi et al., describes a pipeline recovery tool. The rigged-up tool is lowered over the pipeline and engaged with the pipeline such that a fixed claw engages the collar on the pipeline. An ROV is used to cause a movable dog on the tool to engage the collar and then lock the fixed claw in position. The pipeline is then lifted to the surface by a lift arm on the first end of the tool.
U.S. Pat. No. 6,851,895, issued on Feb. 8, 2005 to Jarry et al., describes an improved mooring apparatus and method suitable for use with large offshore vessels. An anchor is fitted with a short chain with one end permanently connected thereto and its free end temporarily placed in a chain locator. The chain locator is positioned so as to be accessible after deployment of the anchor to the seabed. The anchor with a short chain is deployed to the seabed. At some stage, the free end of a mooring chain is lowered to and accurately guided into the chain locator so that the free ends align. A pin is inserted by an ROV to interconnect the two chains. After the chains are interconnected, the combined mooring chain is tensioned so as to be withdrawn from the chain locator.
U.S. Pat. No. 7,134,268, issued on Nov. 14, 2006 to G. Siappas, describes a shackle assembly and a method for installing and/or releasing the shackle assembly subsea. The shackle assembly includes first and second plates mounted on either side of a shackle body eyelet and a shackle pin mounting assembly for use in mounting a shackle pin using a shackle pin pulling tool.
It is an object of the present invention to provide a shackle apparatus which facilitates the ability to lift heavy loads from a subsea location to the surface of the water.
It is another object of the present invention to provide to a shackle apparatus whereby the pin of the shackle apparatus can be easily installed by using a remotely operated vehicle (ROV).
It is a further object of the present invention to provide a shackle apparatus having a pin that can be easily guided through the eyelets of the shackle body by a remotely operated vehicle.
It is still another object of the present invention to provide a shackle apparatus that has a pin that can be guided into position by an ROV and then locked into position after being pushed a desired distance through the eyelets of the legs of the shackle body.
It is still another object of the present invention to provide a shackle apparatus which is easy to use, relatively inexpensive and easy to manufacture.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.